Box wrapping machine

ABSTRACT

A box wrapping machine incorporating (1) a control system which senses and monitors the presence and/or movement of the boxwrapper units through the machine, and (2) a conveying mechanism for separating and discharging the finished boxes.

United States Patent 1.

Shelmire Mar. 19, 1974,

[5 BOX WRAPPING MACHINE 3.321.051 5/1967 Huffman et al 198/24 x 3,616,770 ll/l97l Blyther et al. 83/365 [75] Inventor- Dfimam shelmll'ei churchvlne 3,038,391 6/1962 Von Hofe et al. 93/54 R 1 Pa. 3,657,976 4/1972 3,086,428 4/1963 Albertson et a1. 93/54 R [73] Assgnee' Corporamn San Jose Cahf 3,074,533 l/l963 Ninneman et aL, 198/24 [22] Filed: Mar. 29, 1972 [21] Appl. No.: 239,067 Primary ExaminerAndreW R. Juhasz Assistar'it Examiner-Leon Gilden Related US. Application Data Art ,A r, F --C.E.T1 [63] Continuation-impart of Ser. No. 62,471, Aug. 10. om-ey gen or lrm rpp 1970, abandoned.

52 us. c1; 93/542 [57] ABSTRACT [51] Int. Cl. B3lb 15/00 A box wra ppmg machlne incorporatmg (l) a control [58] F'eld of Search 93/ :52: system which senses and monitors: the presence and/0r v movement of the box-wrapper units through the ma- 1 ,2 chine, and (2) aconveying mechanism for separating ['56] uNlTE g gsz s giqrENTs and discharging the finished boxes. 2,705,905 4/l955 Lange etal. 93/542 '4 Claims, 17 Drawing Figures BOX STAYING MACHINE l U l z-BC 4GL,U|NG MACHINE C MECHANISM D BOX WRAPPING MACHINE K O PAIENIEII IIAR I 9 I974 SIIEEI 1UF9 BOX STAYING MACHINE FIE-I 1 -GLUING MACHINE C BOX REGISTERING MECHANISM D BOX WRAPPING MACHINE K ,0

IM 4 I IIZ BACKGROUND OF THE INVENTION' The field of the present invention concerns those types of wrapping machines wherein an outside wrapper is folded around a box, a box cover or around a similar container.

One prior art wrapping machine of the type above referred to evolved from the wrapping machine disclosed in the U.S. patent of Smith 691,329 and today retains the same general form, structure and mode of operation. Later issued patents concerning the same basic machine are Lange U.S. Pat. No. 2,705,905, and Andresen Jr. et al. U.S. Pat. No. 3,236,161. In general terms, the mode of operation of a typical manual box wrapping system and of the box wrapping machine incorporated therein is as follows: A gluing machine applies adhesive to a wrapper, and deposits the wrapper,

adhesive side up on a main conveyor belt. Alongside the conveying belt is a box staying machine which erects box blanks and places the boxes open end up on a box conveyor that delivers the set-up boxes on an unwrapped box supply table. The boxes on the supply table are located across the main conveyor belt from an operator who manually places a box open end up upon the adhesive face of a wrapper on the main conveyor.

Near the end of the main conveyor the box-wrapper units are sequentially arrested in alignment with the box wrapping machine which is provided with a trans fer carriage that moves across the belt to pick up a boxwrapper unit and deliver it to the box wrapping machine. In a similar system, disclosed in Andresen Jr. et al., U.S. Pat. No. 2,867,158, the box and wrappers are automatically registered and no manual operations are necessary. The latter system includes a box staying machine which delivers finished boxes to a gluing machine. The gluing machine appliesadhesive to wrappers and places the wrappers adhesive side up on a con veyor belt. A registration mechanism operates in conjunction with the gluing machine and overlies the conveyor belt. Each wrapper and a box are :brought into exact alignmentby the registration mechanism, following which the box-wrapper units are delivered in the previously described manner to the box wrapping inachine. This automatic system is faster than the manual system. i

Moved into the box wrapping machine, the boxwrapper unit is located at a folding or forming station where a vertically reciprocating forming block and other mechanism fold the wrapper upward against the sidewalls of the box, inward over the upper edges of the box, and downward against the inner surfaces, of the sidewalls. The wrapped boxes are ejected in the same direction in which they entered the machine, onto a" discharge table for further handling operations.

Several interrelated problems arise when an ordinary box wrapping machine is speeded up to take full advantage of the production rates possible-in an automatic box wrapping system. One problem is that of sensing and controlling the various mechanical manipulations of the box-wrapper unit so that malfunctions can be rapidly detected and the transfer carriage of the box wrappingmachine stopped by the control and sensing system before the machine jams or is damaged. This is difficult to accomplish in the patented machines becauseythe transfer carriage is reciprocated by a driven flywheel eccentrically coupled to the carriage, and the inertia of the flywheel system strongly resists any applied stopping force. A further difficulty when the outputis increased arises from the fact that the adhesive has less time to set. Thus, impact: and relative motion between adjacent boxes butted together causes wrinkling and distortion of the wrapper and transfers glue from box to box. The problems of l) thesensing and control, and (2) the separation of the wrapped boxes until their adhesive is set concern the subject matter of the present invention.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan of atypical box wrapping system incorporating the box wrapping machine of the present invention. t

FIGS. 211 are diagrammatic perspectives illustrating the sequential operations performed upon a box and wrapper in the box wrapping machine.

FIG. 12 is an enlarged elevation viewed in the direction of the arrows l2-l2on FIG. 1.'

FIG. 13 is a sectional plan view taken alongthe plane 13-13 on FIG. 12 at a slightly enlarged scale.

' FIG. 14 is a fragmentary isometric of the transfer carr iage, discharge conveyor, and the transfer carriage drive means of the present invention. v FIG. 15 is an enlarged isometric of the charge conveyor. j

FIG; 16 is an enlarged vertical section taken along lines 16- 16 on FIG. 13.

FIG 17 is a schematic diagram of the electrical control system of the present invention.

DESCRIPTION OFTHE PREFERRED EMBODIMENT A typical automatic box wrapping system 30 (FIG. 1) is, as disclosed in U.S. Pat; No. 2,867,158, provided at its upstream end with a box staying machine A which forms and ejects upwardly open boxes B onto a box conveyor BC. The boxes are fed into a gluing machine C which applies a partial or overallcoating of adhesive to a wrapper W and feeds it, adhesive side up, under a box registering mechanism D. A plunger of the box registering mechanism centers a box over a wrapper and brings the box and wrapper into adhesive contact. The box and wrapper units BW are conveyed away from the registeringmechanism on a vacuum belt conveyor E.

The vacuum belt conveyor E operates intermittently, and each box-wrapper unit BW ultimately comes to rest against a transverse stop mechanism G at a pickup station H. While thus stopped, a reciprocable transfer carriage I of a box wrapping machine K advances FIG. 14.1.8.

pushes the box unit BW and the lower form block LF downward, and the box unit is carried past forming tools adjacent the vertical walls of the box. The outwardly extending flaps of the wrapper W (FIGS. 1 and 511) are folded upward against the side walls of the box B, inward over the upper edges of the walls, and downward against the inner surfaces of the walls.

Meanwhile, the transfer carriage I has picked up the second box unit BW. When the second box unit is transferred to the forming station under the plunger M, the wrapped box is moved by the carriage away from the forming station into gripped relation with a discharge conveyor N. The conveyor moves the wrapped box away from the forming station so that when the second box is finished and transferred to the discharge conveyor, the two boxes are spaced apart. Thus, even if there happens to be any unset adhesive exposed on either box, the boxes only contact each other after they have been ejected onto a receiving table 0, at which time the adhesive has set sufficiently to hold the wrapper-firmly in place and prevent distorted wrappers or gluing the boxestogether.

With more specific reference to FIGS. 2-11, the stop mechanism G is conventional and includes a stop bar 30 that is adjustably positioned along the conveying flight 32 of the vacuum conveyor E to immobilize the box unit BW in centered relation with the path of the box unit toward and through the box wrapping machine K. Two inwardly directed rods 34 of the stop mechanism G have inner ends which are spaced from the box unit at initial delivery, and which allow slight movement of the box unit away from the transfer carriage during the initial part of the transfer operation so that the box closes a normally open microswitch SW1 mounted on one of the rods to initiate the operation of a later described control circuit which is part of the present invention. I

The transfer carriage I (FIG. 3) is similar to that disclosed in Lange et al, supra, and is provided with recip rocable side members 36, each of which includes a shaft 38 that is slidably mounted in a bearing block 40 (FIG. 4). Pedestals 42 (FIG. 14) support the bearing blocks 40 from a slide frame 44 (FIG. 13), on a main frame 43, and an opposed slide frame 46. Each slide frame carries various flap manipulating tools at 48 for folding the wrapper W about the box B, and the slide frames are adjustable toward and away from the vertical path of the box for handling different sizes of boxes. In similar manner, a slide frame 50 (FIG. 12) and an opposed slide frame, not shown, carry similar flap manipulating tools and are also adjustable toward and away from the vertical path of the box.

With brief reference to FIG. 14, the transfer carriage side members 36 are each clamped in a block 52 which is in turn clamped to a drive link 54. A later described drive mechanism 56 is coupled to the center portion of the drive link 54 to reciprocate the transfer carriage. At the opposite end of the transfer carriage spring biased pivotally mounted gripping fingers 58 are cammed inward by the box B as the carriage moves toward its FIG. 3 position, and then pivot toward each other to engage the rear corners of the box. As previously mentioned, the switch SW1 is closed during this box gripping operation.

Forward of each gripping finger 58 is an adjustable stop 60 which engages the front wall of the box, and an ejecting finger 62. When the transfer carriage I moves a second box from the pick-up station H (FIG. 2) to the forming station L (FIG. 4), a previously transferred box unit BW which by this time has been completed is picked up by the ejecting fingers 62 and moves downstream for discharge by the discharge conveyor N.

As the box unit BW is transferred from the FIG. 3 position to the FIG. 4 position, it blocks the light beam of aphotoelectric unit comprising a light projector 64 and a sensor 66 which are associated with the later described control circuit of the present invention. To support the leading flap of the wrapper so that it does not bend downward during transfer of the box unit, vacuum nozzles 70 which are fixed to the transfer carriage engage the comer portions of the leading flap of the wrapper. The nozzles in downstream positions individually overlie support rails 71 (FIG. 14) which support the box unit after they are unsupported by the lower form block LF during discharge from the wrapping machine. At the forming station L (FIG. 4) the box unit BW is supported upon the lower form block LF (FIG. 5) and in vertical alignment with the overhead and descending form blocks UP and MF.

The upper form block UF is mounted on a vertically reciprocable plunger shaft 72, and the middle form block MF is mounted on two vertically reciprocable plunger rods 74. Both form blocks move together downward into the box B and push the upwardly biased lower form block LF and the box unit BW past the flap manipulating tools 48 (FIG. 5) on the slide 50 (FIG. 12) and on the opposed slide, not shown. As shown in FIG. 5, the flap manipulating tools 48 at a first level fold the leading and trailing flaps of the wrapper W upward against the walls of the box B.

At a second, lower level (FIG. 6) other of the flap manipulating tools 48 are actuated to fold the end portions. of the upwardly folded flaps around the adjacent corners of the box and against its lateral end walls .while the form blocks UP and MF are within the box. Progressing downward, the box unit BW (FIG. 7) is moved past further flap manipulating tools 48 which fold the lateral end flaps upward onto the adjacent end walls. At this position, downward movement of the box unit stops, and during a dwell period the upper form block UF is elevated (FIG. 8) and theflap manipulating tools 48 move inward from each side of the'box unit and fold the upstanding free edges of the wrapper into underlying relation with the upper form block while the box unit remains, clamped between the middle and lower form blocks MF and LF.

In order to complete the folding of the wrapper W, (FIG. 9) the upper form block UP is moved downward into the box unit BW as the flap manipulating tools 48 are retracted. The entire assembly returns to the initial starting level where the form blocks are next removed from the completed box. For this purpose, four stripper rods 76 are moved downward through apertures in the form blocks and hold the bottom wall of the box against the lower form block LF while the upper and middle form blocks UP and MF are retracted clear of the completed box unit BW. Meanwhile, the transfer carriage I has gripped the next unfolded box unit BW2 and the ejecting fingers 62 are in a position upstream of the completed box unit.

After the stripper rods 76 are elevated clear of the box as shown in FIG. 11, the transfer carriage I makes its second movement toward the forming station L, to feed the second incoming box unit BW2. The ejecting fingers 62 thus start to eject the finished box, whereupon the box moves into gripped engagement with the discharge conveyor N and out of the box wrapping machine K. In contrast with similar box wrapping machines in which the finished boxes push one another I out of the machine, whereupon any exposed adhesive will glue the finished boxes together, the discharge conveyor N isolates each box until it is discharged from the wrapping machine to prevent wrinkling of the wrapper and transferring glue from one box to another.

The structure to which the present invention is directed, the discharge conveyor N, and the electrical monitoring control system which cooperates with the conveyor and the transfer carriage I, cooperatively result in increasing the output of the box wrapping machine K over the output of a manual type of box wrapping system. The following description is directed primarily to these machine elements and the electrical control system. Other portions of the box wrapping machine K are described only to the extent necessary to disclose the present invention.

Referring to FIG. 12, power for thebox wrapping machine K is supplied by a motor 80 mounted on the frame 43 of the wrapping machine. A drive arrangement, not shown, synchronizes the operation of the wrapping machine K with the gluing machine A and the vacuum conveyor'E. Conveyor E is driven intermittently by the gluing machine. A variable speed belt transmission 82 powers an electrically disengaged clutch .84 for selectively coupling driving power to an input shaft 86. The clutch 84 is unitary with an associated brake which is engaged when the clutch is disengaged. The other end of the input shaft 86 (FIG. 16) extends through a housing 88 that contains a speedreducing gear connection to a vertical cam shaft 90 which drives a barrel cam 92. During each cycle of the box wrapping machine K, the cam 92 makes one complete revolution and the form blocks UP and MF are moved from their FIG. 4 position through the positions illustrated in FIGS. 5-11 (the FIG. 11 position being the same as FIG. 4 position).

For the latter purpose, a cam lever 94(FIG. 12) is pivoted at 96 to a fixed frame member and is provided with a cam follower roller, not shown, which is engaged with a recessed cam track 98 of the barrel cam 92. By means of a connecting rod 100, the cam lever 94 operates an overhead main plunger lever 102 that is pivoted at 104 to a pedestal 106. A link 108 on themain plunger lever is connected to the plunger shaft 72 which actuates the middle form block MF and also controls the upper form block UF. In similar manner, another cam level, not shown, has a cam follower engaged with a cam track 110 to actuate, by means of a connecting rod 111 (FIG. 13), an auxiliary plunger lever 112 (FIG. 1) that is connected to a vertically movable stripper yoke 114 that carries the depending stripper rods 76.

With more specific reference to FIGS. 13-16, the discharge conveyor N and the transfer carraige I, two T- shaped pedestals 116 interconnected by lateral tie bars 1 18 and 1 19 support these structures from the machine frame 43. The drive link 54 (FIG. 16) is provided at each end with an arm carrying follower rollers 120 and 122 (see FIG. 13), respectively rotatable about vertical and horizontal axes, which are guided by an elongate fabricated track 124 that is secured to the adjacent pedestal 116. As previously mentioned, the pedestals 42 which support the upstream end of the transfer carriage I are mounted on the adjustable slide members 44 and 46 (FIG. 12). Thus, it is only necessary to loosen the mounting blocks 52 (FIG. 14) to simultaneously adjust the slide members and the carriage elements 36, 38 and 40 of the transfer carriage for accommodating a different size box. The discharge conveyor N is similarly adjustable, as next described.

Mounting means for the discharge conveyor N (FIG. 14) includes two generally L-shaped mounting plates 128 and 130, best shown in phantom lines in FIG. 15. One convenient manner of adjustably mounting the plates 128 and 130 is to provide a depending flange, as at 132 for the mounting plate 128, which has bolts extending through a slot 134 in the tie bar 119. The other end portions of the mounting plates may be similarly mounted in slotted portions of the tie bar 118. The drive means for the discharge conveyor N includes a gear 136 (FIGS. 13 and 16) which is mounted on the cam driveshaft 90 and is meshed with a smaller gear 138 on a shaft 140. Shaft 140 extends through a bearing bracket 142 atop a part of the frame 43, and is coupled to a chain and sprocket drive train 144.

As clearly shown in FIG. 14, the drive train 144 powers ashaft 146 which is held by a bracket 148 on the adjacent pedestal116. A similar shaftjand bracket 150 and 152 (FIG. 16) is mounted on the other pedestal 116. The shafts146 and 150 carry aligned belt pulleys 154 and 156 that support a drive belt 158. As best shown in FIG. 15, the drive belt 158 is trained around an idler pulley 160 and a driven pulley 162 that are supported by the mounting plate 128. Pulley 162 is secured to a shaft 164 that extends upward through the mounting plate 128 and carries a pulley 166 which is aligned with three idlerpulleys 168 and a tensioning pulley 170. A belt 172 trained around'the pulleys 166, 168 and forms one half of the discharge conveyor N. The other half of the discharge conveyor includes a belt 174 which requires a reverse drive arrangement so that the confronting flights of the belts travel in the same direction.

For reversely driving the belt 174, the drive belt 158 is trained around a driven pulley 176 mounted under the mounting plate 130 and driving a gear 178. A gear 180 of the same size and in mesh with the gear 178 is secured to a shaft 182 that drives a pulley 184 for the belt 174. Three idler pulleysl86 and a tensioning pulley 188 complete the support means for the belt 174. It will be noted that coextensive and simultaneous lateral adjustment of the mounting plates 128 and 130 does not affect thetension of the drive belt 158.

Before next proceeding to the drive arrangement for reciprocating the transfer carriage I, it should be noted that finished box units conveyed along the support rails 71 (FIG. 14) interrupt the light beam, from a projector 190, that otherwise impinges a photoelectric sensor 192. The function of these elements. are later described in conjunction with the FIG. 17 control circuit.

The driven end of the cam shaft 90 (FIG. 16) is lo cated in a housing 194 having an upstanding boss 196 offset from the driveshaft 90 and mounting a pivot shaft 198. An elongate lever 200 is pivoted on the shaft 198 and carries a gear segment 202 on its free end. Intermediate its ends, a lateral arm 203 on the lever 200 is provided with an upstanding cam follower roller 204 which is engaged with a cam track recess on the lower end of the cam 92. Te cam track oscillates the grear segment 202 and is shown at a dwell position which corresponds to that in which a box unit BW is aligned with the forming blocks to allow time for the wrapper to be folded around the box.

Gear segment 202 is meshed with a gear 208 and the drive ratio is such that the gear 208 oscillates through an angle of 180. A boss 210 in the housing 194 supports the lower end of a shaft 212 which is located on the longitudinal centerline of the transfer carriage I and is driven by the gear 208. The upper end portion of shaft 212 extends through a support neck 214 that is fixed to the frame 43, and provides the power for the drive mechanism 56 which reciprocates the transfer carriage I.

It becomes critical, with rapid operating speeds to continuously monitor the operations to avoid jams due to improperly shaped boxes fed into the box wrapping machine, or due to possible other malfunctions that might interrupt the normal movement or wrapping of a box unit. These general functions are carried out by the control circuit of FIG. 17, which includes five camoperated switches that are not illustrated in the present application. Each switch is operated by an individual cam 248 (FIG. 16) that is mounted on an upper extension of the cam driveshaft 90, and this rotates once per box-wrapping cycle.

Referring to FIGS. 2 and 13, the incoming box unit BW is arrested by the stop bar 30 and is adjacent the actuator of the switch SW1. When the transfer carriage I is moved to position the gripping fingers 58 (FIG. 3) beyond the rear corners of the box unit, the box unit is pushed against the switch actuator and the switch contacts close to momentarily energize the control system. Switch SW1 (FIG. 17') is in series with a control relay CR1 in a line 250 extending across power input lines Lland L2. Control relay CR1 is thus energized, and its holding contacts CR-l in a line 252 close. At this time the cam operated switch SW2 in a line 252 is closed, and the control relay CR1 remains energized as the transfer carriage gripping fingers 58 pull the box unit toward the box wrapping machine. An electrical As the box unit BW (FIG. 3) is moved by the transfer carriage between the photolectric sensor elements 64 and 66 (the former being energized by a transformer T1, line 249) the cam operated switch SW3 in a line 254 is closed. A control relay CR2 is in series with switch SW3 and the photoelectric sensor 66, and is thus energized when a box unit interrupts the light beam from the projector 64. Immediately after the box unit passes through the light beam, one set of contacts of the cam operated switch SW4 in a line 256 are closed. In the event that the relay CR1 closed, but control relay CR2 did not close due to a malfunction which prevented transfer of the box unit across the photoelectric sensor 66, the electrically operated clutch and brake unit 84 (FIG. 12) is actuated to disengage driving power to the box wrapping machine and set the brakes.

If no box transfer occurs after the control relay CR1 is actuated, a delay timer DT, line 256, is energized through the closed contacts of switch SW4, normally closed contacts CR2-2, line 255, of the control relay CR2, and the switched contacts CR1-2 of the control relay CR1. Contacts DT-l of the timer DT close and energize a clutch solenoid S, line 258. Thus energized, the solenoid S disengages the clutch of the electrically operated clutch and brake unit 84 (FIG. 12) so that no power is transmitted to the box wrapping machine from the motor 80, and the brake is set to rapidly stop the machine. However, if the normal transfer of the box unit occurs, both control relays CR1 and CR2 are energized, thus opening the contacts CR2-2, line 255, and opening contacts CR1-3, line 256 so that the delay timer DT is electrically isolated and the transfer of the box unit is completed to the forming station L (FIG. 4).

A control relay CR3, line 253, is connected to another set of contacts of the cam operated switch SW4. An electrical path is thereby completed through control relay contact CR2-1, line 253, and the cam operated switch SW2 to energize the control relay CR3 while the wrapper W is being folded around the box B. Normally open control relay holding contacts CR3-1, line 260, close, and in conjunction with the now closed cam operated switch SW6, the control relay CR3 remains'energized. It will be seen that the control relay CR3 is only energized if the ciontrol relays CR1 and CR2 signalled that a box unit was transferred (no malfunction). Following the operation of the control relay CR3 as described, the cam operated switch SW2, line 252, opens, and the control relays CR1 and CR2 are deenergized This conditions the control system for the above described operations to repeat with the next incoming box unit. v

At this point the box unit at the forming station L has been wrapped and ejected into gripped relation with the belts of discharge conveyor N (FIG. 1 1).-At a given point in the overall cycle, the finished box passes under the light beam projector (FIGS. 13 and 14) and blocks the beam from the photoelectric sensor 192 (FIG. 17, line 262). The sensor 192 is operative, when its light beam is interrupted, to energize a control relay CR4 and its normally open holding contacts CR4-1, line 261, close. In conjunction with the closed cam operated switch SW6, the control relay CR4 remains energized after the finished box clears the photoelectric sensor 192 and is discharged onto the table 0 (FIG. 1). The finished box has now generated a control signal that it has clearedthe box wrapping machine. Next, the cam operated switch SW5, line 264, closes. If there is no such control signal generated, some malfunction exists between the forming station Land the receiving table 0, and the brake solenoid S is again energized to disengage the clutch, set the brake, and stop the box wrapping machine. This action is initiated by the cam operated switch SW5. Upon closing, the contacts of switch SW5 enerfize the delay timer DT by means of normally'closed control relay contact CR4-2, line 263, and the switched contacts CR3-2 of the control relay CR3, whereupon the delay time contacts DT-l energize the solenoid S to actuate the clutch and brake 84 (FIG. 12). If the photoelectric sensor 192 is actuated by a box interrupting its light beam, the control relay CR4 is energized as previously described, and-the solenoid are electrically isolated by the normally closed but 9 now open contacts CR3-3, line 264, and CR42, lin 263.

It will be apparent that the Fig. 17 control system monitors a series of events which, once broken, will result in the stopping of the machine so that the malfunction can be corrected. A further important aspect of the control system is that it is initiated by a box unit in position for transfer into the box wrapping machine, thus allowing an occasional missing box unit on'the conveyor E without interrupting the operations upon a box already in the wrapping machine. The control systern monitors the feed, wrapping and discharge of the boxes, and interrupts the operation if malfunctions occur, so as to prevent damage to the machine which could otherwise result from the higher'than usual velocities of the components, while the discharge conveyor system N interspaces the finished boxes and maintains the orientation and control of the finished boxes, so that they are delivered to a predetermined location at a predictable time, thereby facilitating further operations by other machinery. The control system detects the progressive movement of the boxes and is adapted to quickly and automatically interrupt the operations until a jam or malfunction can be corrected. This minimizes damage to the machine, reduces the number of scrap boxes, and allows the operator greater time for attendant duties away from the wrapping ma chine.

Although the best mode contemplated for carrying out the present invention has been herein shown anddescribed, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

What is claimed is: i

1. In a box wrapping machine including vertically reciprocable form blocks for folding an adhesively coated wrapper around a box at a forming station of the machine, a horizontally reciprocable transfer carriage 0nd driving pulley connected to said second gear, a powered pulley laterally adjacent one of said mounting plates, an idler pulley laterally adjacent the other of said mounting plates, all of said pulleys lying in a common plane, and an endless drive belt trained around said pulleys, said conveying flights thus moving in a common direction and being arranged for simultaneous and coextensive interspacing adjustment without interrupting their conveying function.

2. Apparatus according to claim 1 and box support means comprising a support track secured to each of said mounting plates, each track extending laterally inward below the adjacent conveying flight, the interspacing adjustment of said conveying flights thus effecting adjustment of said box support means.

3. A box wrapping system comprising a conveyor for delivering a box and adhesively coated wrapped unit to a pickup station, a box wrapping machine comprising a forming station having vertically reciprocable form blocks for folding the wrapper around the box adjacent said pickup station, and a transfer carriage movable between said sattions to transfer a box-wrapper unit from said pickup station to said forming station; the improvement comprising detector means at said pickup station for detecting the presence of a box-wrapper unit ready for pickup upon advance of said transfer carriage, sensing means intermediate said pickup and forming stations for sensing the passage of a boxwrapper unit picked up by said carriage and conveyed between said stations, power means including an electrically operated clutch for transmitting driving power to said form blocks and to said transfer carriage, control means operating in timed relation with said transfer carraige, and a control circuit responsive to said control means, to said detector and to said sensing means for disengaging said clutch when a box-wrapper unit is detected at said pickup station but is not picked up by downstream of said forming station and repetitively movable across said forming station to transfer the wrapped boxes to adownstream delivery station, a conveying flight at each side of said delivery station for frictionally engaging the opposed ends of the wrapped boxes, means for synchronously driving said flights away from said delivery station to preserve the interspacing of the wrapped boxes, an individual mounting plate for each conveying flight, means mounting said plates for movement toward and away from each other to accommodate different sizes of boxes between said flights, said means for synchronously driving said flights comprising individual laterally aligned drive shafts mounted on the respective mounting plates for said conveying flights, a first drive pulley mounted onone of said drive shafts, a first gear mounted on the other of said drive'shafts, a second gear meshed with said first gear and carried by the adjacent mounting plate, a secthe carriage and hence is not sensed by said sensing means disposed intermediate said pickup and forming stations, said control circuit leaving said clutch engaged if said carriage advances to pick up a boxwrapper unit but no unit is present at said pickup sta tion, so that the wrapping of a previously picked up unit can be completed.

4. The box wrapping system of claim 3, wherein said box wrapping machine includes a discharge station for discharging wrapped boxes from the wrapping machine, a wrapped box receiving station, a wrapped box sensor for sensing the passage of a wrapped box from said discharge station to said receiving station, said control circuit including means for disengaging said clutch in response to a signal from said timed control means when a box is not sensed by said wrapped box 

1. In a box wrapping machine including vertically reciprocable form blocks for folding an adhesively coated wrapper around a box at a forming station of the machine, a horizontally reciprocable transfer carriage downstream of said forming station and repetitively movable across said forming station to transfer the wrapped boxes to a downstream delivery station, a conveying flight at each side of said delivery station for frictionally engaging the opposed ends of the wrapped boxes, means for synchronously driving said flights away from said delivery station to preserve the interspacing of the wrapped boxes, an individual mounting plate for each conveying flight, means mounting said plates for movement toward and away from each other to accommodate different sizes of boxes between said flights, said means for synchronously driving said flights comprising individual laterally aligned drive shafts mounted on the respective mounting plates for said conveying flights, a first drive pulley mounted on one of said drive shafts, a first gear mounted on the other of said drive shafts, a second gear meshed with said first gear and carried by the adjacent mounting plate, a second driving pulley connected to said second gear, a powered pulley laterally adjacent one of said mounting plates, an idler pulley laterally adjacent the other of said mounting plates, all of said pulleys lying in a common plane, and an endless drive belt trained around said pulleys, said conveying flights thus moving in a common direction and being arranged for simultaneous and coextensive interspacing adjustment without interrupting their conveying function.
 2. Apparatus according to claim 1 and box support means comprising a support track secured to each of said mounting plates, each track extending laterally inward below the adjacent conveying flight, the interspacing adjustment of said conveying flights thus effecting adjustment of said box support means.
 3. A box wrapping system comprising a conveyor for delivering a box and adhesively coated wrapped unit to a pickup station, a box wrapping machine comprising a forming station having vertically reciprocable form blocks for folding the wrapper around the box adjacent said pickup station, and a transfer carriage movable between said sattions to transfer a box-wrapper unit from said pickup station to said forming station; the improvement comprising detector means at said pickup station for detecting the presence of a box-wrapper unit ready for pickup upon advance of said transfer carriage, sensing means intermediate said pickup and forming stations for sensing the passage of a box-wrapper unit picked up by said carriage and conveyed between said stations, power means including an electrically operated clutch for transmitting driving power to said form blocks and to said transfer carriage, control means operating in timed relation with said transfer carraige, and a control circuit responsive to said control means, to said detector and to said sensing means for disengaging said clutch when a box-wrapper unit is detected at said pickup station but is not picked up by the carriage and hence is not sensed by said sensing means disposed intermediate said pickup and forming stations, said control circuit leaving said clutch engaged if said carriage advances to pick up a box-wrapper unit but no unit is present at said pickup station, so that the wrapping of a previously picked up unit can be completed.
 4. The box wrapping system of claim 3, wherein said box wrapping machine includes a discharge station for discharging wrapped boxes from the wrapping machine, a wrapped box receiving station, a wrapped box sensor for sensing the passage of a wrapped box from said discharge station to said receiving station, said control circuit including means for disengaging said clutch in response to a signal from said timed control means when a box is not sensed by said wrapped box sensor. 